#rational_number  an integer or a fraction
  supertype:  real_number__real  any rational or irrational number
  subtype:  fraction  the quotient of two rational numbers
     subtype:  mantissa__fixed-point_part__fixedpointpart  the positive fractional part of the representation of a logarithm; in the expression log 643 = 2.808 the mantissa is .808
     subtype:  common_fraction__simple_fraction  the quotient of two integers
        subtype:  half__one-half__onehalf  one of two equal parts of a divisible whole; "half a loaf" or "half an hour" or "a century and one half"
           subtype:  fifty_percent__fiftypercent  a half expressed as a percentage
           subtype:  mediety__moiety  one of two (approximately) equal parts
        subtype:  one-third__onethird__third__tierce  one of three equal parts of a divisible whole; "it contains approximately a third of the minimum daily requirement"
        subtype:  two-thirds  two of three equal parts of a divisible whole
        subtype:  one-fourth__onefourth__fourth__quarter__fourth_part__twenty-five_percent__quartern  one of four equal parts; "a quarter of a pound"
        subtype:  three-fourths__threefourth  three of four equal parts; "three-fourths of a pound"
        subtype:  one-fifth__onefifth__fifth__fifth_part__fifthpart__twenty_percent  a fifth part
        subtype:  one-sixth__onesixth__sixth  a sixth part
        subtype:  one-seventh__oneseventh__seventh  a seventh part
        subtype:  one-eighth__oneeighth__eighth  an eighth part
        subtype:  one-ninth__oneninth__ninth  a ninth part
        subtype:  one-tenth__onetenth__tenth__tenthpart__ten_percent__tenpercent  a tenth part; one part in ten
        subtype:  one-hundredth__onehundredth__hundredth__onepercent  one part in a hundred
        subtype:  one-thousandth__onethousandth__thousandth  one part in a thousand
        subtype:  one-millionth__onemillionth__millionth  one part in a million
        subtype:  one-billionth__onebillionth__billionth  one part in a billion
        subtype:  one-trillionth__onetrillionth__trillionth  one part in a trillion
        subtype:  one-quadrillionth__onequadrillionth__quadrillionth  one part in a quadrillion
        subtype:  one-quintillionth__quintillionth  one part in a quintillion
     subtype:  improper_fraction  a fraction whose numerator is larger than the denominator
     subtype:  proper_fraction__properfraction  a fraction with a numerator smaller than the denominator
        subtype:  decimal_fraction__decimalfraction__decimal  a proper fraction whose denominator is a power of 10
           subtype:  circulating_decimal__circulatingdecimal__recurring_decimal__recurringdecimal__repeating_decimal__repeatingdecimal  a decimal with a sequence of digits that repeats itself indefinitely
     subtype:  complex_fraction__complexfraction__compoundfraction  a fraction with fractions in the numerator or denominator
     subtype:  continued_fraction__continuedfraction  a fraction whose numerator is an integer and whose denominator is an integer plus a fraction whose numerator is an integer and whose denominator is an integer plus a fraction and so on

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